Modern vehicle engines generally require a heat transfer fluid (liquid coolant) to provide long-lasting, year-round protection of their cooling systems. The primary requirements of the heat transfer fluids are that they provide efficient heat transfer to control and maintain engine temperature for efficient fuel economy and lubrication, and prevent engine failures due to freeze-up, boiling-over, or over-heating. An additional key requirement of a heat transfer fluid is that it provides corrosion protection of all cooling system metals over a wide range of temperature and operating conditions. Aluminum corrosion protection is particularly important. Beyond metal protection, corrosion protection helps the heat transfer fluid to fulfill its primary function of transferring excess heat from the engine to the radiator for dissipation.
There is an ongoing need for heat transfer fluids having good fast and/or extended corrosion protection.